RpNation

Been asking this question since seeing shapeshifter Jack and wicked teeth caster. Narita adaptation curse please. Don't make it go the way of Baccano S2.

Flat is the most based Master ever short of Gudao. He's also some sort of super magus bred from some project that only Zelretch and his buddies know about - though he doesn't have Mystic Eyes like some might have suspected.

In Volume 4, Jack reveals two Noble Phantasms - From Hell and Natural Born Killers. From Hell turns him into an FGO demon (not a pillar) and transforms the area into a traditional fire and brimstone vision of hell because people thought Jack was a demon straight out of hell. Natural Born Killers makes copies of him because people thought that Jack the Ripper might have been a group of conspirators instead of a loli.

Based Dumas doesn't really do much in this volume, though he does get the orders to send out that one police chief's crazy Noble Phantasm wielding SWAT squad and uses a Noble Phantasm called Musketeer's Masquerade. I have no idea how he fits with Dantes, the Drama CD makes it pretty explicit that he wasn't a fictional character.

Felt was cool too. I only read the manga though, and a while back, when it hadn't even introduced the true servants yet.